in the Present study, nimodipine-PVP
solid dispersion was investigated toenhance the
dissolution rate of nimodipine (NMDP),
a poorly water-soluble substance, and toformulaiC the dosage forms with fast-release properties. The dissolution properties of NMDP-PVPcoprecipitate and physical mixture were compared. The physical states of NMDP in both newly-madeand one-yak-old samples of
solid dispersion were also investigated by X-ray diffraction analysis.The dissolution rate of NMDP from the tablets and capsules of coprecipitate was compared with thatof two kinds of commercial tablets. The resultS shoWed that solid
Dispersion gave much higherimprovement than Physical mixture in the dissolution rate. In 5 min, 89% of the ding was releasedfrom solid dispersion, and 45% from physical mixture.Powder X-ray diffraction pattern showed thatNMDP was present in amorphous or molecular form in the solid dispersion while it was in crystallineform in physical mixture.There was no appearanCe of crystallization in solid diSPersion after oneyear storage in a sealed glass bottle under room temperature. Capsules and tablets of coprecipitateboth showed fast-release propefties, and the drug dissolution fate from the former was greater thanthat from the latter, suggesting that the compressing pressure could influence the dissolution rate. Itwas also demonstrated that the dissolution rate of NMDP from the selected capsules was muchgreater (about three to four times) than that from the two kinds of commercial tablets.